Extreme pressure lubricant



Patented June 24, 1941 EXTREME PRESSURE LUBRICANT Henry G. Berger andDarwin E. lBadertscher, Woodbury, and Francis M. Seger, Pitman, N. Jassignors to Socony-Vacuum Oil Company, Incorporated, New York, N. Y., acorporation of New York No Drawing.

17 Claims.

This invention, which is a continuation in part 01' that disclosed inour copending application Serial No. 177,891, filed December 3, 1937,has to do in a general way with the art of lubrication and is moreparticularly concerned with the development of a lubricant compositionadapted for use under extreme pressure conditions.

As is well known to those familiar with the art, the ordinary type ofhydrocarbon lubricant,

Application October 23, 1940, Serial No. 362,372

comprised only of a petroleum fraction, is incapable of withstanding theenormous pressures encountered between engaged surfaces in varioustypesof modern machinery, such as the hypoid gears used in motorvehicles. This fact has led I to the development of the so-calledextreme pressure lubricant, which is comprised of a suitable carryingagent, such as mineral oil, containing a minor proportion of aningredient which under the extreme pressure conditions encountered willprovide or form between the engaged surfaces a lubricating film capableof withstanding these high pressures. Ingredients of the type justreferred to are known as extreme pressure ingredients or extremepressure (E. P.) bases, and numerous materials have been proposed forsuch use. Among the various E. P. bases which have been proposed andwhich have met with varying degrees of success are organic materialswhich contain sulfur and chlorine. Our present invention is related tothis general type of compound.

It is a primary object of this invention to provide an extremepressurelubricant which contains'a new and novelsulfur-and-chlorine-containing material or compound capable of givingare more desirable irom the standpoint of odor.

The perchloromethylmercaptan derivatives which we have found to beparticularly useiul as E. P. bases may be broadly divided into twogeneral classifications: namely, (1) products obtained by reactingperchloromethylmercaptan with organic compounds containing an active"hydrogen or an active metal atom, or both; and

(2) products obtained by reacting perchloromethylmercaptan withunsaturated organic materials such as animal and vegetable oils, crackedpetroleum stocks, etc. Reaction products of the type encompassed byclass 2 above were made the subject of our application Serial No.177,890, filed December 3, 1937. The present application is broadlydirected to the reaction products of group 1, wherein vthe secondaryreactant is an organic compound containing an active hydrogen atom or anactive metal atom or both.

Typical compounds contemplated under the broad aspect of this inventionas organic compounds containing an active hydrogen atom or an activemetal atom are: (a) aromatic hydrocarbons (specifically disclosed andclaimed in our copending application Serial No. 358,207, filed September25, 1940); (b) organic amines (specifically disclosed and claimed in ourcopending application Serial No. 358,286, filed September 25, 1940); (0)organic compounds having the general formulaROX, where R is alkyl, aryl,aralkyl, or alkaryl and X is hydrogen or the hydrogen equivalent of ametal (this latter group includes the alcohols, phenols, metalalcoholates, metal phenolates, etc., and is specifically disclosed andclaimed in our application Serial No. 358,288, filed September 25, 1940)and (d) compounds having the general formula RSX, where R is alkyl,aryl, aralkyl, or alkaryl and X is hydrogen or the hydrogen equivalentof a metal (this group of compounds includes the mercaptans,mercaptides, the thiophenols and their metal derivatives and isspecifically disclosed and claimed in our copending application SerialNo. 362,373, filed concurrently herewith).

In its more specific aspect our present invention is directed to stillanother class of perchloromethylmercaptan reaction products, wherein thecompound containing active hydrogen or active metal is one selected fromthe class consisting of the organic thio acids and their metal salts.The organic thio acids and their corresponding metal derivativescontemplated for obtaining the reaction products forming the specificsubject matter of this invention may be represented by I the generalformula least one Y being sulfur; X represents hydrogen or the hydrogenequivalent of a metal and R represents alkyl, aryl, aralkyl, alkaryl orone of the radicals RS; R'O-or wherein R represents a hydrocarbonradical and R" represents hydrogen or a hydrocarbon radical. Typicalthio acids which with their metal salts are contemplated herein forreaction with perchloromethylmercaptan are listed below with .theirgeneral formulae.

Carbothiolic acids (R.CO.SH)

Carbolthionic acids (R.CS.OH) Carbithionic acids (R.CS.SH)Monothiocarbonic acids (R.O.CO.SH) Dithiocarbonic (xanthic) acids(R.O.CS.SH) Trithiocarbonic acids (R.S.CS.SH) Thiocarbamic acids (R.(R)N.CS.SH)

Perchloromethylmercaptan, the primary reactant used in synthesizing thereaction products contemplated herein, is a chlorinated substitutedsulfur chloride having the formula ClsC-SCI. It can be prepared by thechlorination of carbon disulfide according to the method of Helfrich andReid (Jour. American Chem. Soc. 43, 591 (1921) For example, carbondisulfide containing about .4 per cent by weight of iodine waschlorinated in the absence of direct sunlight at a temperaturemaintained below 25 C. until the volume of the reaction mixture haddoubled. This crude reaction product, which contains carbontetrachloride and sulfur chlorides in addition toperchloromethylmercaptan, can be used in the preparation of the reactionproducts contemplated by this invention, but it is preferable to purifythe crude product by distillation on a. water bath at 100 0., followedby steam-distillation. Subsequent vacuum-distillation of the materialrefined.

in this manner indicated that the steam-distilled material waspractically pure.

The procedure for preparing the general class of reaction productscontemplated herein may be obtained from the following examplesdescribing the synthesis of reaction products which typify those formingthe specific subject matter of the present invention.

EXAMPLE ONE Reaction of perchloromethvlmercaptan with potassium ethyl:ranthate Potassium ethyl xanthate (potassium ethyl dithiocarbonate) wasslowly added to an equal weight of perchloromethylmercaptan in anacetone solution. The strongly exothermic reaction required watercooling. The reaction mixture was drowned in water, and the heavy redliquid which separated was washed with dilute sodium sulfide and driedby filtration. This reaction product contained 41.3 per cent sulfur and23.6 per cent chlorine.

EXAMPLE Two Reaction of perchloromethylmercaptan with potassium amyldithiocarbonate Potassium amyl dithiocarbonate was reacted withperchloromethylmercaptan in a procedure similar to that described above,and the small excess of perchloromethylmercaptan was removed from theproduct of reaction. After the water was separated from the product, thelatter was cent sulfur and 27.7 per cent chlorine.

Exnmm Tam Reaction of Perchloromethylmercaptan with crude commercialsodium ethyl trithiocar- Donate Two molecular proportions of cmdecommercial sodium ethyl trithiocarbonate (assuming its purity as percent) were reacted with one molecular proportion ofperchloromethylmercaptan in acetone solution. 'Theperchloromethylmercaptan used in this reaction was the crude materialabove referred to, and the product obtained was isolated by filtering,distilling ofi the solvent, drying azeotropically with benzol, andfiltering again. The product obtained through this procedure contained60.9 per cent sulfur and 6.5 per cent chlorine.

EXAMPLE FOUR Reaction of perchloromethylmercaptan and sodium dimethyldithiocarbamate A water solution of sodium dimethyl dithiocarbamate wasprepared by shaking 35 grams (0.25

mole) of the compound with 250 cc. of water. The turbid solution wasadded to 45 grams (.25 mole) of perchloromethylmercaptan in petroleumether, and the'mixture stirred for 1 hour at room temperature. There wasan initial temperature rise of 10 C., which was brought down by means ofa water bath. The petroleum ether solution was then water-washed and theether distilled off to yield 29 grams of a dark brown oil.

EXAMPLE FIVE Reaction of perchloromethylmercaptan and ethyl :canthicacid Ethyl xanthic acid (CzHaOCSSH) was formed by dissolving 60 grams(0.375 mole) of potassium ethyl xanthate in water cooled in ice to under5 C. and then adding an excess of sulfuric acid. The xanthic acid thusformed was extracted with cold petroleum ether and added to a coldsolution of 46.5 grams (0.25 mole) of perchloro methylmercaptan inpetroleum ether with the temperature maintained at about 0 C. Themixture was then allowed to warm up slowly to room temperature, afterwhich it was water washed and the solvent removed under vacuum. Theproduct was topped to a pot temperature of 72 C. at 2.7 mm. in a streamof nitrogen gas to yield a yellow oil.

In the foregoing examples we have mentioned several typical compounds ofthe specific class contemplated herein which may be reacted withperchloromethylmercaptan to obtain effective E. P. ingredients. Othercompounds falling into the aforesaid specific classification of organicthio acid and their metal salts are as follows:

CzI-IsCOSH thiopropionic acid CzHsCOSK potassium salt of thiopropionicacid C6H5CSOH thiobenzoic acid CsHsCSSH dithiobenzoic acid- CsI-IsCSSNasodium salt of dithiobenzoic acid C4H9CSSNa sodium salt of dithiovalericacid CaHaOCOSNa sodium salt of propylthiocarbonic acid CQI'I-ESCSSHethyl trithiocarbonic acid (CI-maNCSSH dimethyl dithiocarbamic acid Todemonstrate the effectiveness of the reaction products contemplated bythis invention as extreme pressure lubricant ingredients we haveprepared and tested compositions comprised of these ingredients andmineral oil as the carrying agent. More specifically, we haveadded aminor proportion of each of the reaction products prepared according tothe foregoing illustrative examples to a mineral oil having a SayboltUniversal viscosity of 80-90 seconds at 210 F. and have subjectedsamples of such blended lubricants to the Almen Pin test described byWolf and Mougey, Proc. A. P. I., 1932, pages 118-130, and the S. A. E.test described in S. A. E. Journal 39, 23-.4 (1936). These twotests arecommonly accepted in the art a standards to determine the extremepressure characteristics of a lubricant. In Table I below we show theresults obtained with such tests, using the oil without the additionagent and samples of the same oil blended with perchloromethylmercaptanderivatives of the type contemplated by this invention.

*These values were obtained at 1000 R. P. M. instead I of 755 R. P. M.The blank oil failed in the test at 1000 R. 'P.,M. with a 20 pound load.

From the foregoing examples it will be seen that theperchloromethylmercaptan condensation products contemplated by thisinvention are highly efllcient extreme pressure lubricant bases. Theamount of these materials used may vary from say .5 per cent to 20 percent, but in general lower percentages ranging from .5 per cent to percent are preferred.

' Although we have indicated in the foregoing description that a minerallubricating oil is a preferred carrying agent for the extreme pressureingredients contemplated by our invention,

, it is not our intention that the invention be limited to anyparticular carrying or blending medium, but the invention includesbroadly-extreme pressure lubricants containing theperchloromethylmercaptan condensation products dissolved, dispersed oremulsified in any other suitable carrying mediumsuch, for example, asfatty vegetable and animal oils; light petroleumhydrocarbons such askerosene, eta; benzene and related hydrocarbons; etc.

Weclaim:

1. An extreme pressure lubricant composition comprising a hydrocarbonoil and in admixture therewith a minor proportion of the productobtained by the reaction of perchloromethylmercaptan with a compoundselected from the group consisting of organic compounds '\containingreactive hydrogen atoms and organic compounds containing reactivemetallic atoms, said reaction product containing both sulfur andchlorine and being present in the oil in an amount suflicient toincrease its load-carrying capacity.

alcohols; esters; ethers,

2. An extreme pressure lubricant composition comprising a hydrocarbonoil and in admixture therewith a minor proportion of the product obtamedby the reaction of perchlorome'thylmercaptan with a compound selectedfrom the group consisting of organic thio acids and their metal, salts,said reaction product containing both sulfur and chlorine and beingpresent in the oil in an amount sufiicient to increase its loadcarryingcapacity.

3. An extreme pressure lubricant composition comprising a hydrocarbonoil and in admixture therewith a minor proportion of the productobtained by the reaction of perchloromethylmercaptan with a compoundhaving the general formula wherein the Ys represent oxygen or sulfur andat least one Y is sulfur, X represents hydrogen or the hydrogenequivalent of a metal and R is selected from the group consisting ofhydrocarbon radicals and the radicals R'S-, RO and N.- RII/ wherein R isa hydrocarbon radical and R" is selected from the group consistingof'hydro-.

gen and hydrocarbon radicals.

4. An extreme pressure lubricant comprising a hydrocarbon lubricant oiland in admixture therewith a minor proportion of the product obtained bythe reaction of perchloromethylmer-- captan with an alkalithiocarbonate, said prodnot containing both sulfur and chlorine.

5. An extreme pressure lubricant comprising a hydrocarbon lubricant oiland in admixture therewith a minor proportion of the product obtained bythe' reaction of perchloromethylmercaptan with an alkali thiocarbamate,said prod-v uct containing both sulfur and chlorine.

6. An extreme pressure lubricant comprising a hydrocarbon oil and inadmixture therewith a minor proportion of the product obtained by thereaction of perchloromethylmercaptan with an alkali alkyldithiocarbonate.

7. An extreme pressure lubricant comprising a hydrocarbon oil and inadmixture therewith a minor proportion of the product obtained byreacting perchloromethylmercaptan with an alkali alkyl trithiocarbonate.

8. An extreme pressure lubricant comprising a hydrocarbon oil and inadmixture therewith a minor proportion of the product obtained byreacting perchloromethylmercaptan with an alkali'alkyl dithiocarbamate.

' 9. An extreme pressure lubricant comprising a hydrocarbon oil and inadmixture therewith a minor proportion of the product obtained byreacting perchloromethylmercaptan with a compound selected from thegroup consisting of: potassium ethyl xanthate; potassium amyl tri-.thiocarbon-ate; sodium ethyl trithiocarbon'ate and sodium dimethyldi-thiocarbamate.

10. An extreme pressure lubricant composition comprising a minorproportion of the chlorineand-sulfur-containing product obtained by thereaction of perchloromethylmercaptan with a compound having the generalformula wherein the Y's represent oxygen or sulfur andv at least one Yis sulfur, X represents hydrogen or the hydrogen equivalent of ametal'and R is selected from the group consisting of hydrocarbonradicals and the radicals R'S, R'O-, and

wherein R is a hydrocarbon radical and R." is selected from the groupconsisting of hydrocarbon radicals and hydrogen, the said product beingin admixture with a major proportion of a carrying medium, whichcomposition when ap-' plied to metallic bearing surfaces will form alubricant film capable of withstanding extreme pressure conditions.

11. An extreme pressure lubricant composition comprising a minorproportion of the chlorineand-sulfur-containing product obtained by thereaction of perchloromethylmercaptan with the metal salt of an organicthio acid, in admixture with a major proportion of carrying medium,which composition, when applied to metallic bearing surfaces, will forma. lubricant film capable of withstanding extreme pressure conditions.

12. An extreme pressure lubricant composition comprising a minorproportion of the chlorineand-sulfur-containing product obtained by thereaction of perchloromethylmercaptan with an alkali thiocarbonate, inadmixture with a major proportion of carrying medium, which composition,when applied to metallic bearing surfaces, will form a lubricant filmcapable of withstanding extreme pressure conditions.

13. An extreme pressure lubricant composition comprising a minorproportion of the chlorineand-sulfur-containing product obtained by thereaction of perchloromethylmercaptan with an alkali thiocarbamate, inadmixture with a major proportion of carrying medium, which composition,when applied to metallic bearing surfaces, will form a lubricant filmcapable of withstanding extreme pressure conditions.

14. An extreme pressure lubricant composition comprising a minorproportion of the chlorineand-sulfur-containing product obtained by thereaction of perchloromethylmercaptan with a compound selected from thegroup consisting of potassium ethyl xanthate; potassium amyltrithiocarbonate; sodium ethyl trithiocarbonate; and sodium dimethyldithiocarbamate, the said product being in admixture with a majorproportion of carrying medium and the said lubricant composition, whenapplied to metallic bearing surfaces, forming a lubricant film capableof withstanding extreme pressure conditions.

15. An extreme pressure lubricant comprising a minor proportion of thechlorine-and-sulfur to metallic bearing surfaces, will form a lubricantfilm capable of withstanding extreme pressure conditions.

17. An extreme pressure lubricant comprising a minor proportion of thechlorine-and-sulfur containing product obtained by the reaction ofperchloromethylmercaptan and ethyl xanthic acid in admixture with amajor proportion of a carrying medium, which composition, when appliedto metallic bearing surfaces, will form a lubricant film capable ofwithstanding extreme pressure conditions.

HENRY G. BERGER. DARWIN E. BADERTSCHER. FRANCIS M. SEGER.

